[RFC] merge `user_picker` into `profile`

[susnux]

In #57539 we merged the user_picker app into server.
But this app basically only adds a reference picker for the user profile.
So from my point of view it is basically part of the profile app itself - it will not really work if you disable profiles in general. Also because is basically provides only the reference widget / picker for the profile app.

So maybe we should reduce the number of apps and keep it simple by just merge this few files directly into the profile app? This will reduce overhead of loading another app on every request.

cc @AndyScherzinger @julien-nc

[AndyScherzinger]

Sounds reasonable and to help with maintenance. One aspect we would loose and ad a solution for would be the ability to turn it off. They way you could now by disabling the app.

Yet would also be interested in @julien-nc pov.

[susnux]

One aspect we would loose and ad a solution for would be the ability to turn it off. They way you could now by disabling the app.

We could simply add a second config option next to this one:

[julien-nc]

Sure, makes sense. I can do that later this week.